Fluorescent lighting circuits and parts for use therein



June 13, 1950 E. H. SALTER FLUORESCENT LIGHTING CIRCUITS AND PARTS FOR USE THEREIN Flled July 12, 1946 INVENTOR [/FNEST A4 Sm. TEE.

flurounr/c CUTWITHND F5551- TrPE 311cm r51? ATTORNEY Patented June 13, 1950 FLUORESCENT LIGHTING CIRCUITS AND PARTS FOR USE -T-I-IEREIN Ernest H. Salter, Great Kills, N. Y., assignor to Electrical Testing Laboratories, -Inc., New York, N. Y., a corporation of New York Application July 12, 1946, Serial No. 683,053

2 Claims. (01. 315-400) The present invention relates to fluorescent lighting circuits and parts for use therein.

The typical circuit for preheat-Starting hot cathode fluorescent lamps employs a ballast to control voltage and current flow to the lamps and each lamp is provided with a starter whose function is to introduce the cathodes into the circuits so they can be heated before voltage is applied to strike the arc. The starters are active in circuit only during the starting period and as long as the lamp is lighted the starters are inactive. Should the lamp, however, fail to light, the starter comes back into the circuit so as to reheat the cathodes and try to relight the lamp. This operation causes a blinking of the lamp.

The starting current,-i. e., the current for heating the hot cathodes, is at least 50% higher, and in some cases almost twice as high, as the normal operating current for the lamp. While this starting current is not continuous, yet it has been found that the blinking of the lamp or lamps contributes to overheating and possible burnout of the ballast.

In many cases it is found that the heating of the ballast with a blinking lamp is practically the same as though the starter were short circuited so that current flowed through the cathodes without interruption.

The refusal of the lamp to start usually comes from the fact that the lamp is worn out so that once it refuses to start it continues to refuse to start, and to avoid the continual blinking of the lamp it is usual to employ special starters which have an automatic cut out switch effective after a few attempts to start to permanently open the starting circuit for the lamp. The automatic cut out is provided with a resetting mechanism whereby the lamp circuit can be restored. The ability to cut out the lamp not only eliminates the blinking of the lamp but avoids overheating in the transformer which is likely to result from a blinking lamp in the circuit.

These automatic cut out type of starters, i. e., those which operate to open the starting circuit of a blinking lamp, have heretofore been made in such a way as to be interchangeable with the non-cut out type of starter and only one form of socket has been available, with the result that even though a fixture were designed for use of the automatic cut out type of starter, there is nothing to prevent the substitution of the noncut out type of starter.

The design of the usual ballast has been such that it would not exceed a safe temperature when the lamp or lamps were blinking provided the ballast were fully exposed so as to dissipate the heat. Such ballast is, however, likely to be used nder such conditions that the ballast cannot dissipate the excessive heat developed by blinking lamp operation.

In fluorescent lighting equipment there is, therefore, the hazard of having restricted or reduced heat dissipating capacity about the ballast so that excessive heating of the ballast may result because of the use of the non-cut' out type of starter which hazard is not present where the automatic cut out type of starter is used in the circuit. On account of the interchangeability of the starters as heretofore made, it is, therefore, impossible to predict with certainty that the temperature rise of the ballast in an installation under adverse conditions will be a safe temperature rise.

The present invention contemplates providing the circuit for the preheat starting hot cathode fluorescent lamp with an arrangement of starter and starter socket which insures the use of the proper starter.

According to the present invention, the starter socket and the automatic cut out starter are provided with parts which do not interfere with the normal use of the starter, but which do interfere with the insertion of a non-cut out starter of the common type.

The accompanying drawings illustrate one form of starter and starter socket and a typical circuit for the preheat starting hot cathode fluorescent lamp.

In the drawings:

Figure 1 is an elevational view of an improved starter socket;

Figure 2 is an end view with parts broken away to show interior construction;

Figure 3 is a side elevational view of a starter;

Figure 4 is an elevational view taken from the contact end of the starter;

Figure 5 is a view illustrating the starter and starter socket assembly in operating relation; and

Figure 6 is a wiring diagram.

The starter socket It in Figures 1, 2 and 5 may be any one of the conventional forms of starter socket with standard dimensions, except for the provision of a lug or projection l l which is in the center of the socket opening. The usual contacts for the starter connection are indicated at l2-l 2. This projection ll may be molded integral with the body of the starter socket.

The starter l5 shown in Figures 3 and 4 and designated by the letter S in Figure 6 may be any of the standard well known forms of automatic out out type of starter. Such starters have the usual contact pins l6-l6 adapted to enter the bayonet slots I! of the starter socket and engage the contacts l2. They may have a reset device such as a push button [8 or may be of the automatic reset type. All the parts of such starters are carried by an insulating base plate 20. The present invention contemplates providing this base plate 20 with an aperture 2! midway between the contact l5l 6 and of a size to receive the projection or post I I carried by the starter socket.

This arrangement makes it possible to use with the starter socket having the projection such as l I, only such starter as is provided with the opening 2| in the base so that the starter can be inserted in place. When the lamp circuit, such for example as is illustrated in Figure 6, is provided with these special starter sockets, it is, therefore, impossible to use any starter which does not have the apertured base to admit the lug on the starter side. This makes it possible to protect the ballast against overheating incident to the blinking of the lamp which might occur were it possible to use the wrong kind of a starter.

Since it is obvious that the invention may be embodied in other forms and constructions within the scope of the claims, I wish it to be understood that the particular form shown is but one of these forms, and various modifications and changes being possible, I do not otherwise limit myself in any way with respect thereto.

What is claimed is:

1. In a fluorescent lamp operating circuit having a ballast and a preheat starting hot cathode lamp and wherein the heat dissipating capacity of the ballast is such as to avoid attaining a predetermined temperature rise on continuous operation of the lamp and attain excessive heating on intermittent lamp operation occasioned by failure of the lamp to start, a lamp starter circuit including an automatic cut out and reset type starter having contact pins from the base, the base bein apertured between the pins, and a starter socket having pin receiving openings into which the pins are inserted to hold the starter in place and a 7 projection entering the aperture in the starter base, whereby the insertion of a similarly contoured starter with imperforate base is Prevented. 2. Means for preventing the use of non-cut out type starters in a fluorescent lamp circuit having a ballast of insuflicient radiating capacity to dissipate the heat incident to continued repeated failures of the lamp to start, which comprises an automatic cut out reset type starter having contact pins from the base, the base being apertured between the pins, and a starter socket having pin receiving openings into which the pins are inserted to hold the starter in place and a projection entering the aperture in the starter base, whereby the insertion of a similarly contoured starter with imperforate base is prevented.

ERNEST H. SALTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 731,779 Hundhauser June 23, 1903 1,901,040 Peroni et a1 Mar. 14, 1933 2,124,182 Braun July 19, 1938 2,276,829 De Reamer Mar. 17, 1942 

